The production of aldehydes and alcohols by the reaction of olefins with carbon monoxide and hydrogen is well known and well described in many U.S. patents, including U.S. Pat. No. 2,880,241, to Hughes. The general reaction for the preparation of aldehydes is: EQU CO+H.sub.2 +C.sub.x H.sub.2x .fwdarw.C.sub.x H.sub.2x+1 CHO(I)
From this point, the aldehyde produced in Reaction I may be hydrogenated to produce an alcohol by the reaction EQU C.sub.x H.sub.2x+1 CHO+H.sub.2 .fwdarw.C.sub.x H.sub.2x+1 CH.sub.2 OH(II)
This second reaction is not always desired, and, in some particular instances, the preferred product is the aldehyde rather than the alcohol The catalytic process of the present invention discloses one method of obtaining the aldehyde product almost to the exclusion of the alcohol. As the catalyst of the present invention is a heterogeneous catalyst that can be easily separated from the products of the reaction, further treatment of the products, particularly the aldehydes, may be accomplished in a separate reactor, with or without a catalyst, to obtain other reaction products of the aldehydes, including the alcohols, if so desired. The persons skilled in the chemical arts will be already in possession of the knowledge of how to react aldehydes to other useful chemical species.
The carbon monoxide and hydrogen mixture required to react with the olefin or olefins would be readily and economically available if the synthesis gas, which is a generic term for a variety of mixtures of carbon monoxide and hydrogen, produced by conventional coal gasification processes was free from sulfur contaminants, particularly hydrogen sulfide. Sulfur compounds, however, are known to be poisons of the catalysts known in the prior art, so costly desulfurization processes are required in the preparation of a synthesis gas for the desired reaction. For example, see Carberry, Chemical and Catalytic Reaction Engineering, McGraw-Hill, 1976, at 396.
Further, as recognized and noted by Blaskie, et al., in U.S. Pat. No. 4,361,711, the prior art has, in general, been conducted in the liquid phase, using various solvents for controlling concentration of soluble reactants, reactants and catalysts which are present in a homogeneous single phase system. Because the reactants, products, and catalysts are present in the same phase, this type of hydroformylation reaction requires a separation step, after the actual hydroformylation stage, to recover the catalyst from the product stream. Catalyst recovery and regeneration has been one of the major costs and investments in commercializing these liquid phase processes. These costs are especially pernicious when the catalysts contain rare metals.
It should be noted that many of the known effective catalysts used in the liquid phase processes are the metal carbonyls and their modified forms. This type of homogeneously catalyzed reaction is often referred to as the "Oxo" process.
In attempts to avoid the expensive separation steps after hydroformylation for homogeneous phase catalysts and to minimize the costs of catalyst losses in the product, various researchers have used polymers or oxides as anchoring agents for metal complex catalysts as well as use of mixed metal oxides as catalysts. Although a heterogeneous phase catalyst can be achieved, these catalysts still suffer from sulfur poisoning, and they have additional problems of poor activity, selectivity, and thermal stability. Ideally, an excellent hydroformylation catalyst should be active and selective to a desired product, i.e., aldehyde; be resistant to sulfur poisoning; and be a solid phase catalyst to minimize purification of the products and catalyst loss in the product.